Concentrating plant with circulation of liquid between a liquid/vapour separation vessel and a separate heating member

摘要

In concentrating plant wherein the liquor being evaporated is circulated between a heater and a liquid/vapour separation vessel, the fresh feed liquor is supplied to the plant at a temperature and pressure greater than the temperature and pressure of the circulating liquor and is introduced in part into the inlet side of the heater, and in part directly into the separation vessel. Part of the preheated liquor may also be injected into the return pipe leading from the heater back to the separation vessel. The invention permits high circulation rates to be maintained without the formation of so much vapour in the heater that the heat-exchange surfaces are no longer adequately wetted with liquor. The concentration of spinning bath liquors is referred to. In the Figure, separation vessel 20 is connected by pipes 23, 24 to heater 25 which is provided with supply and discharge pipes 26 and 27 respectively for heating medium. The feed liquor pipe 28 branches into two pipes 30 and 31, of which pipe 30 opens into the inlet end of heater 25, while pipe 31 branches into two further pipes 33 and 34. Pipe 33 opens into the vapour space of the separation vessel 20; a pipe 34 leads to a jet 35 disposed in the nozzle-shaped return pipe 24. Valves 36, 37 and 38 enable the distribution of feed liquor to be varied between the various pipes. Vapours leave the separation vessel via pipe 21; and the concentrated liquor is discharged through pipe 22.